Answer:
Vaporization
Step-by-step explanation:
Vaporization is the change of a specie to the gaseous state. To 'disappear' in this case simply means to change to the gaseous state.
Substances with high vapour pressure tend to be easily converted to vapour phase. Hence if Glade air freshener gel 'disappears' easily, then it has a high vapour pressure and is easily converted to vapour (gas).